power_shell_scripting.md

power shell scripting

commands

• basic format of commands is VERB-NOUN
• .ps1 extension is used to save powershell scripts
• we need to use ise scripting enviroment , we can allow extra inputs valled parameters
• cmdlet is the name of eventlog

1. start-transcript = it stores session history in a file

2. get-help

3. get-command

4. get-member - discover objects , property , methods , objects has properties like color size etc , it has methods like action specific to object amd event handlers , when event happens eg open , close etc

5. get-command -noun history

cmdlets

1. get-help < cmdlet-name >

   • -full : explains parameter
   • -examples: show examples
   • get-help * - shows all

2. to find a command

   • to find using service get-command -noun services
   • to find using modules get-command -module vmware
   • we ca shoten the command using alias
   • default copy or cp
   • get-alias give us list of all alias
   • get-alias -definition get-service - check if alias exist
   • to create alias - set-alias -name name -value select-string

3. some famous alias

   • cmdlet alias description
   • foreach-object % perform and opern agains each set of input objects
   • format-list fl formats output as list
   • format-table ft format output as table
   • get-command gcm info about cmdlets
   • get-content cat gs type get contents of item at loc
   • get-process gps ps get process that is running
   • get-help help
   • sort-object sort
   • select-object select
   • stop-process kill
   • write-object echo write

synatx , variables

• by default execution policy is restricted we need to change it

  • get-executionpolicy = to get current policy
  • set-exectuionpolicy policy < name > = to set policy
  • het-help about_execution_policies

• powershell.exe -exec bypass = to allow scripts to run

vairables

• $a we use $ to set or use variable

  • $a =7 set
  • $A output
  • $a = dir c:\
  • $a | sort-object -property name
  • dir c:\ | sort name -desc

• types , int string object

  • [int] $a = 7 explicit declaration
  • $ days = "sun","mon","tue" collection of objects
  • we use index $days[0] , we can use range(..) [2..4] [-1] for reverse . $days.length give no. of length

• special characters

  • $_ : current pipeline object
  • $ture, $false ,$null
  • get-childitem variable : show them all

• paranthesis( ) = used for loops , if and switch statements

  • if($num gt 7){ "bigger than 7"}
  • foreach ( $f in $files ) { $f.name}

• curly braces { } = used as script blocks that is command inside other commands

  • ls | %{ $_.length/1024 } = print length of each file divided by 1024

• quotes

  • double and single are same except when variable is declared in one
  • $a ="nitish"
  • write-host "hello i am $a " - hello i am nitish
  • if we use 'hello $a ' - hello $a

• backtick ( ` ) it's escapes the dollar sign